For those interested in old cars.

[MrWolf]

Interesting stuff, no point in having extra horses that you can't use because the engine isn't breathing right. It's always the art of compromise, between big numbers and useable horses. 

How much torque would you expect to get at the wheels with those mods?

[big jim]

Not sure to be honest but the old car at 218bhp was giving 233 Nm at 5500 rpm (at the crank) 

 

 

the rolling road print out for the new one shows 165 wheel BHP and I think 143 wheel torque if I’m reading it right, this car also has a LSD so it puts the power down a lot better on the curves! 

 

[Enterprisingwestern]

4 hours ago, big jim said:

My Mini is a later model supercharged one which has Teflon coated blades and is about 10bhp more standard than my early model one that I scrapped last month 

 

The old mini had a superchip bluefin fitted and was putting out about 230-240 crank BHP with all the same mods my new one has (my mechanic swapped them off my old car) however on the new one I’ve not bothered with the superchip and I’m going to spend on getting it properly mapped, the only other change I’m going to do is bigger injectors, the map is a by bitronic and will cost me about £480 to be done but will be set up on a rolling road at a mini specialist in Cambridgeshire (1320 mini) and it will custom to my car as opposed to the generic ‘superchip’ which when last dyno’d you could see by the graph it wasn’t getting enough fuel at the top end of the Rev range

 

the chances are the new one will be less BHP than the old one but have more go as it’s going to be fuelling right (with no pops and bangs) 

 

 

 

How old are you?!!!

 

Mike.

[big jim]

1 hour ago, Enterprisingwestern said:

 

How old are you?!!!

 

Mike.

why?

[alastairq]

Uh-oh....

[MrWolf]

I have always found it odd that the dynamometer technicians in this country still use the old fashioned horsepower rather than kilowatts, but insist upon using Newton metres for the torque figures. 

Perhaps it's because of the numbers?

233 Nm = 171.8 ft/lb torque.

Which doesn't look quite so hot against 218 bhp. 

The issue is that shorter stroke engines running higher revs to achieve maximum horsepower are going to lose out when putting that power through the transmission and onto the road.

Running with minimal power but wringing the most "work" out of it is something that British engineers were rather good at, particularly when avoiding high road taxation rates.

For example, the car nearest where I am sitting is a 1965 Triumph Herald 1200, a whopping 1147cc and 48bhp.

It has a single carburettor and only two wires going to the engine.

That 48bhp gives 61ft/lb of torque.

61ft/lb = 82.71Nm.

If we knew that we could extrapolate these figures without variation we have the following:

The Mini has 4.54 times more bhp than the Triumph, so if we multiply both bhp and Nm figures by 4.54, the relative torque figure for the Triumph would be 375Nm. Though I doubt that the universal joints would like that very much!

I often find where people are given figures to quote for their cars, they're always the ones that sound good. It's quite natural. 

I suppose that I have been spoilt, the last old car I owned put out 325bhp 445 ft/lb through a LSD straight out of the box when new in 1959. That's 603Nm or two new Range Rovers in modern car speak.

[big jim]

The thing with BHP is its universally understood, if I was looking at a car ans someone said it’s such and such kilowatts or Nm I wouldn’t have a clue whereas if the said it’s such and such brake horse power then I have some sort of idea/benchmark in my head 

 

and yes, I quote crank BHP as it makes it look better 

[MrWolf]

You're right, I think that people do get obsessed with horse power figures, a big number is impressive to most people, but it's the work that number can do which is important and has been understood by engineers since the invention of the horse gin. 

Ever seen a tug of war contest between a 2000bhp custom built sled pulling tractor and an 8HP steam traction engine? It's hilarious.

[Hobby]

 

[MrWolf]

That's the fella.

[Hobby]

I suspect he had a bit of a weight advantage, though!

[APOLLO]

You can't beat raw horsepower. Turn the speakers up and don't breathe as the locos power past !!

 

 

Brit15

[boxbrownie]

9 minutes ago, Hobby said:

I suspect he had a bit of a weight advantage, though!

Are you saying the driver is a bit over weight......how rude 

[Kickstart]

The traction engine has a major traction advantage. And the connection between the 2 will lift up the driving wheels on the tractor.

 

All the best

 

Katy (who has a liking for small peaky  2 strokes , and playing with the gearbox).

[MrWolf]

1 hour ago, Hobby said:

I suspect he had a bit of a weight advantage, though!

 

At the most, the traction engine will be around 20 tons. A reg tractor pulls that easily. It's all about torque.

[Anglian]

Horse power is just one part of the equation what's equally telling is power to weight. As Colin Chapman said 'add lightness'. 

 

An S1 Elise manages to out-run an awful lot of other cars, especially through the twisty stuff, with just 118bhp.

Edited December 15, 2020 by Anglian

[MrWolf]

That's where power to weight ratio comes in. There's an awful lot of car drivers who look at one of my seventy year old bikes at the traffic lights and assume that it will hold them up, so they try to barge past.

Cue dented ego.

[alastairq]

At one time {IIRC?} the fastest thing from 0 to 30 mph was a scooter...

[big jim]

1 hour ago, MrWolf said:

That's where power to weight ratio comes in. There's an awful lot of car drivers who look at one of my seventy year old bikes at the traffic lights and assume that it will hold them up, so they try to barge past.

Cue dented ego.

my Mini upset a Porsche 4x4 away from the lights the other week, I knew I wasn’t going to have him past a certain point but off the mark I was ahead of him until about 50mph!

 

(Then he probably changed to 2nd gear!)  

[Kickstart]

2 hours ago, MrWolf said:

 

At the most, the traction engine will be around 20 tons. A reg tractor pulls that easily. It's all about torque.

Torque is just power divided by revs. So just use a lower gear to get torque at the wheels!

And don’t try and tow something which is lifting your driving wheels.

 

All the best

 

Katy

[gordon s]

4 hours ago, APOLLO said:

You can't beat raw horsepower. Turn the speakers up and don't breathe as the locos power past !!

 

 

Brit15

Enjoyed watching that, but perhaps someone can explain something that has always puzzled me. Probably an easy answer, but blowed if I know.....

 

All couplings appear to be the same, but in the UK there is generally just one or two loco’s at the front. That means the first coupling behind the train has to be strong enough to withstand the weight of the whole train when pulling away from a standstill.
 

Are couplings and coupling mechanisms designed with a maximum weight in mind and as such all are engineered for a maximum weight. If you went beyond that point would the chain link stretch and break or the hook split into two? Maybe the hook pulls out of the buffer team?

 

Edit: I was thinking in terms of 3 link couplings not the modern versions

Edited December 15, 2020 by gordon s

[steve1]

22 minutes ago, Kickstart said:

Torque is just power divided by revs. So just use a lower gear to get torque at the wheels!

And don’t try and tow something which is lifting your driving wheels.

 

All the best

 

Katy

 

And don't, as I once did, put so much weight in the boot of an Avenger it makes the steering dangerously light...

 

steve

[MrWolf]

27 minutes ago, Kickstart said:

Torque is just power divided by revs. So just use a lower gear to get torque at the wheels!

And don’t try and tow something which is lifting your driving wheels.

 

All the best

 

Katy

 

That drag tractor will have ridiculously low gearing, the reason his front wheels are lifting is that he is giving it the beans to go forward, but the steamer is dragging him and several tons of earth the opposite way.

[PhilJ W]

2 hours ago, MrWolf said:

That's where power to weight ratio comes in. There's an awful lot of car drivers who look at one of my seventy year old bikes at the traffic lights and assume that it will hold them up, so they try to barge past.

Cue dented ego.

 

1 hour ago, alastairq said:

At one time {IIRC?} the fastest thing from 0 to 30 mph was a scooter...

A Trolleybus?

[MrWolf]

6 minutes ago, steve1 said:

 

And don't, as I once did, put so much weight in the boot of an Avenger it makes the steering dangerously light...

 

steve

 

Or pile an old lathe up in the back of a Bedford CA without securing it.

Romped up a 1 in 10 hill until the front wheels started to lift when the 1/2 ton lathe slid backwards.

Luckily for us we were stupid teenagers, swung the van into a gateway and reversed the rest of the way up the hill.